German Patent No. 44 35 419 A1, which relates to a "control system for proportioning the fuel of an internal combustion engine" and in which the intake air temperature value is used among other things for the determination of a warm start case, may be pointed out as exemplary of the extensive conventional methods in connection with the use of a signal of the intake air temperature in the context of the control of an internal combustion engine.
Primarily reasons relating to space requirements in the area of the internal combustion engine are the reason that sensors for the intake air temperature are usually not mounted in the immediate vicinity of the internal combustion engine but rather, for example, in the air filter housing, in a mass air flow meter, in the throttle valve connector or in combination with an intake manifold pressure sensor. The temperature measured with these sensors does not then correspond to the actual intake temperature in the vicinity of the intake valve which is relevant to the operation of the internal combustion engine when the intake air can become heated on the warm walls of the intake manifold on its path to the internal combustion engine. In internal combustion engines with exhaust gas recirculation, there is the additional heating of the intake air by an admixture of the hot exhaust gas.
It has now been shown that it is not always possible to obtain optimal results in relation to the influence of the intake air temperature with the conventional systems.